The independent roles of hypoglycemia and seizure activity in producing neurological deficits and cognitive[unreadable] impairment in children with insulin-dependent (Type I) diabetes are not completely understood. The studies[unreadable] proposed will test the hypothesis that the combined insult of brain glucopenia with the added metabolic[unreadable] demand of seizures produces increased neuronal death, but also structural synaptic alterations that underlie[unreadable] neuronal dysfunction in the absence of cell death. The objective of this project is to develop in vivo imaging[unreadable] methods to detect and observe serial changes in dendritic spines of cortical neurons following hypoglycemia[unreadable] combined with seizures, to evaluate whether there are synergistic injurious effects. To examine these issues,[unreadable] creation of a cranial window with a novel laser surgery technique combined with two-photon microscopy will[unreadable] enable in vivo imaging of dendritic structures in YFP expressing cortical neurons serially monitored at baseline[unreadable] and during hypoglycemia without and with focal seizures produced by 4-aminopyridine (4-AP).